Simulation models of water distribution networks (WDNs) are fundamental for management, operational and monitoring purposes. Typical usage of the models range from pumps scheduling, management of the pressures at the nodes of the network, identification of faults (e.g., leaks), monitoring of water quality, etc.
WDN models available to utility companies, however, are often inaccurate due to the imperfect representation of the complete physical process and the incomplete knowledge of all of the required parameters. The uncertainty in the models is typically reduced with the calibration, where the parameters are adjusted such that pressures and flows predicted by the model match a set of actual observed field data to some desirable or acceptable level. Many methods have been proposed for the solution of the calibration problem. Methods for the optimal placement of sensors around the network have also been studied, in order to maximize the sensitivity of certain desired parameters to the collected data and therefore improve the quality of the estimation.
A major issue with the reduction of uncertainty in WDN models is the scarcity of measurement points around the network, with the number of parameters to be adjusted usually being much larger than the available measurements. Calibration can therefore only be successful on a selected subset of parameters of the model, which usually leaves significant uncertainty in major areas of the WDN model. Another issue, also related to the poor availability of measurement points, is the exact localization of the source of uncertainty. In some situations, in fact, an inconsistency between model predictions and field measurements could ambiguously be related to a number of different parameters or to a fault (e.g., leaks) in the network, the problem of exactly inferring the source of uncertainty could be undetermined with the available measurements.
Therefore, improved techniques for reducing uncertainty in WDN models that solves the problem of having scarce measurement points around the network would be desirable.